Direct Hydroxylation of Benzene with Hydrogen Peroxide Using Fe Complexes Encapsulated into Mesoporous Y-Type Zeolite

Mesoporous Y-type zeolite (MYZ) was prepared by an acid and base treatment of commercial Y-type zeolite (YZ). The mesopore volume of MYZ was six times higher than that of YZ. [Fe(terpy)2]2+ complexes encapsulated into MYZ and YZ with different Fe contents (Fe(X)L-MYZ and Fe(X)L-YZ; X is the amount of Fe) were prepared and characterized. The oxidation of benzene with H2O2 using Fe(X)L-MYZ and Fe(X)L-YZ catalysts was carried out; phenol was selectively produced with all Fe-containing zeolite catalysts. As a result, the oxidation activity of benzene increased with increasing iron complex content in the Fe(X)L-MYZ and Fe(X)L-YZ catalysts. The oxidation activity of benzene using Fe(X)L-MYZ catalyst was higher than that using Fe(X)L-YZ. Furthermore, adding mesopores increased the catalytic activity of the iron complex as the iron complex content increased

Synthesis of LaFeO3 perovskite-type oxide via solid-state combustion of a cyano complex precursor: The effect of oxygen diffusion

The effect of oxygen diffusion on the thermal decomposition kinetics of La[Fe(CN)6]·5H2O has been explored. In particular, the critical conditions under which LaFeO3 can be synthesized via solid-state combustion of this cyano complex precursor were analytically and numerically investigated. Thermal analysis experiments as well as simulations showed that the oxygen diffusion enhancement facilitates the formation of a self-propagating combustion front during the decomposition of La[Fe(CN)6]·5H2O. As a consequence, the sample undergoes local overheating that raises its temperature by several hundreds of degrees. This enables the production of LaFeO3 perovskite-type oxide with a minimum contribution of external heat resources. Although the self-propagating high-temperature method has already proven to be successful for the synthesis of perovskite-type oxides from cyano complex precursors under oxygen atmosphere, we will show that under the appropriate settings, air can be used instead. Moreover, the temperature of the front is related to the ease of oxygen diffusion. Therefore, the surface area and the crystal size of LaFeO3 perovskite-type powders obtained via solid state combustion have been controlled by controlling the gas flow rate at which the sample has been exposed during the treatmen

Self-propagating high-temperature synthesis of LaMO3 perovskitetype oxide using heteronuclearcyano metal complex precursors

The decomposition of La[Fe(CN)6]·5H2O and La[Co(CN)6]·5H2O under different atmospheres has been analyzed by thermogravimetry (TG) and differential thermal analysis (DTA). In addition, the decomposition temperature at different sample locations was monitored for sample masses around 2 g of La[Fe(CN)6]·5H2O and La[Co(CN)6]·5H2O, when they were calcined for 1 h at temperatures ranging from 200 to 400 °C in a controlled gas-flow system. Results showed that, the large enough of the cyano complex precursors undergo combustion when they are decomposed under oxygen atmosphere. X-ray diffraction results revealed that perovskite-type oxides crystallize due to the overheating of the process. As a result, it has been possible to produce LaFeO3 and LaCoO3 perovskite-type oxide powders by SHS under oxygen atmosphere using La[Fe(CN)6]·5H2O and La[Co(CN)6]·5H2O as a precursor. The effect of the ignition temperature has been investigated. The specific surface area of the perovskite-type oxides produced via SHS using heteronuclearcyano metal complex as a precursor is significantly higher than that of other LaMO3 produced using the same technique but obtained from other type of precursor

Selective Oxidation of Thioanisole with Hydrogen Peroxide using Copper Complexes Encapsulated in Zeolite: Formation of a Thermally Stable and Reactive Copper Hydroperoxo Species

[Cu­(terpy)]²⁺ complexes encapsulated into Na-Y zeolite ([Cu­(terpy)]²⁺@Y) were prepared, and their catalytic activities for the oxidation of sulfides using hydrogen peroxide were investigated. Several spectroscopic results, as well as elemental analysis, demonstrated the formation of [Cu­(terpy)]²⁺ complexes in supercages of Y-zeolite. [Cu­(terpy)]²⁺@Y exhibited high selectivity for the oxidation of thioanisole into methylphenylsulfoxide when H₂O₂ was used. The kinetic study of this oxidation at the catalyst [Cu­(terpy)]²⁺@Y suggests that the reaction of [Cu­(terpy)]²⁺ species with H₂O₂ is the rate-determining step. The oxidation of thioanisole, benzene, and 2-phenylethylamine using [[Cu­(terpy)]²⁺@Y]*, which was prepared from the reaction between [Cu­(terpy)]²⁺@Y and H₂O₂, quantitatively proceeded to methylphenylsulfoxide, phenol, and 2-amino-1-phenylethanol, respectively. The reaction of [Cu­(terpy)]²⁺@Y and H₂O₂ was found to yield thermally stable but active Cu^II-OOH species in [Cu­(terpy)]²⁺@Y

The Deployment of a Newly Developed Proximal Release-Type Colonic Stent Is Feasible for Malignant Colorectal Obstruction near the Anal Verge: A Single-Center Preliminary Study

Introduction: Colonic self-expandable metallic stents are widely used to treat malignant colorectal obstructions. Stent placement in lesions near the dentate line causes problems, including severe pain due to difficulty in positioning the stent accurately. Therefore, a proximal release-type stent was developed to overcome this issue, and this preliminary study aimed to investigate its efficacy and safety. Patients and Methods: This research enrolled eight patients with malignant colorectal obstructions up to 10 cm from the anal verge who required placement of the newly developed proximal release-type colonic stent. The primary outcome was the clinical success rate, and the secondary outcomes were the technical success and adverse events rates. Results: The technical and clinical success rates were 87.5% each, and the mean procedure time was 25.5 ± 22.0 min. The mean procedure time in the rectosigmoid colon was significantly longer than that in the rectum. Only one (12.5%) patient had stent migration, and neither anal pain nor tenesmus was observed. Discussion: The stent was highly effective in treating lesions near the anal verge, and it might contribute to the expansion of indications for colorectal stents for lesions near the dentate line. However, the indications for rectosigmoid colon lesions should be cautiously considered